Pump



1965 J. A. MILETI 3,200,755

PUMP

Filed Sept. 10, 1962 3 Sheets-Sheet l INVENTOR.

Jog-PH AMI/L E77 Aug. 17, 1965 J. A. MlLETl 3,200,755

PUMP

Filed Sept. 10, 1962 3 Sheets-Sheet 2 INVEN TOR.

dosgpfi 4. M4 57/ w. Ji/HJW'Q.

1965 J. A. MILETI 3,200,755

PUMP

Filed Sept. 10, 1962 5 Sheets-Sheet 3 INVENTOR.

dog-PH 14. fif/zfrl 8AM? AM 4 T'TORIVI') United States Patent PUMP Joseph A. Mileti, Oxnard, Calif., assignor to The Bentlur Corporation, South Bend, Ind., a corporation of Delaware Filed Sept. 10, 1962, Ser. No. 222,399 4 Claims. (Cl. 103-113) This invention relates to a centrifugal pump that is self gas and vapor purging. More particularly, this invention is concerned with means for increasing the efficiency of the purging of deleterious gas and vapors which can collect at the inlet of centrifugal pumps.

As seen in prior art Patents Nos. 2,461,865; 2,500,227; 2,581,828; 2,804,022; and 2,850,983; it has been a well established practice to purge gases and vapors from a liquid to not only insure pure liquid supply by the pump, but to prevent pump inlet constriction and even blocking by a gas or vapor vortex. Such units, as disclosed by the above patents, have combined a vapor pump with the centrifugal liquid or solid pump and have provided annular recesses adjacent the inlet of the latter for vapor collection. It has, however, been found that the running clearance of the vapor pump is critical to the efficiency of same. Thus, it is not unusual to expect clearances of .0035 to .0045 and possibly less, and this has led to diflicult and expensive manufacturing techniques.

In order to increase vapor to liquid ratio performance, I have devised a method to eliminate the clearance prob- Jam and in fact the clearance itself to increase the efficiency of a means within a centrifugal liquid pump trapping and collecting gas and vapor from a liquid as it passes through an inlet of the centrifugal impeller.

It is also an object of this invention to provide a means to maintain contact of a vapor pump means with the surrounding housing in the vapor inlet and discharge areas.

In addition, it is an object of this invention to provide a bearing surface to a pump housing structure to allow a pump means to contact same when rotating.

Still another object is to resiliently press a valve means against a rotating member to prevent fluid passage and/ or collection therebetween.

A further object of my invention is to provide a pressure controlled member for contact of a pump means with adjacent structure to increase the efficiency of said pump means.

As may be realized by those skilled in the art, other and further object may be set forth in the following description of the accompanying drawings in which:

' FIGURE 1 is a sectional view of a centrifugal pump constructed in accordance with my invention;

FIGURE 2 is a sectional view of still another centrifugal pump with yet another embodiment of my invention incorporated therein; and

FIGURE 3 is a sectional view of a modified means for maintaining bearing contact of a pump valving system in accordance with my invention.

In more detail, with reference to FIGURE 1, I show a pump housing having an inlet port 12 connected to a liquid supply (not shown) and an outlet port 14. Within the housing a shaft 16 is supported, as by bearings 18, which shaft has a splined end 20 and a threaded projection 22. Thus, a motor may be adapted to (through splined end 20) drive a pump in a cavity 24. The pump is a two-part assembly having a front impeller 26 and a rear impeller 28 shown as being constructed with one and the same body between them which is keyed or otherwise drivingly secured to shaft 16 and held axially by a nut. I

An annular recess 30 or pocket is provided in the inlet 12 adjacent the front impeller 26, and a passage 32 connects this recess with a chamber 34 behind the rear im- 3,200,755 Patented Aug. 17, 1965 ice peller 28. Another annular recess 36 is formed in the housing 10 to form an outlet duct for impeller 26, which outlet duct leads to outlet 14. Housing 10, and more particularly chamber 34, is provided with an additional passage 40, which passage 40 may be connected to the fluid supply mentioned or be united with an overboard vent or the like.

Within the chamber 34, I place an annular member 42 which member is provided with a drilled passage 46. Member 42 is urged towards the rear impeller 28 by spring 50.

As may be readily appreciated by those skilled in the art, the member 42 is provided with a machined or bearing type surface to allow rubbing contact with the impeller.

In operation, the pump is given by a motor (not shown) which is connected as aforementioned. As the front impeller rotates, it draws a liquid from the inlet 12, but, due to the change in direction of the liquid as directed by impeller 26, a vortex or similar flow of gas or vapor is created adjacent the housing corner leading to the pump cavity of the housing.

As the front impeller rotates, the rear impeller 28 also rotates, and in so doing, maintains a running contact with member 42 due to spring pressure forces being exerted thereon. This means that the fluid film thickness between the impeller 28 and inlet and outlet member 42 is substantially eliminated. Thus, the intake and discharge efiiciency of the impellers 26 and 28 is greatly improved, and the maximum vapor liquid ratio performance is realized.

I have also found that the vapor pressure induced by pump vanes 28 to flow from the inlet may be utilized to maintain the seal contact with the vanes of a pressure response member 44. In such a pump the housing 10 is provided with passages 32a and 40a which form inlet and exhaust passages, respectively, for the gas or vapor chamber 48. Such a pump construction is shown by FIGURE 2 of the drawings. As may be obvious to those skilled in the art, the passage 46a is provided with an opening adjacent the rear impeller 28 which is of lesser diameter than the passage 46a which allows a pressure buildup which maintains contact between member 44 and pump vanes 28 as above.

Another way of arriving at an optimum vapor liquid ratio is to make the pump impeller a split construction, as in FIGURE 3. In more detail, FIGURE 3 shows a pump housing having an inlet 112, an outlet 114, and a pump cavity 124 similar to that shown in FIGURE 1. In addition, a pump impeller 52 is mounted to a shaft 116, which shaft is supported by bearings 118 to the housing, and driven by a motor (not shown) that is connected to splined end of the shaft.

As is also found in the embodiment of FIGURE 1, an annular recess is provided adjacent the inlet to cavity 124, which recess is connected by passage 132 to a chamber 54 provided in the housing and connected by passage 56 to the cavity 124. Another chamber 58 is provided in the housing and, as with chamber 54, is connected by a drilled passage 60 to cavity 124, and to an exterior opening 62 in the housing by another passage 64.

The cavity 124 is also provided with an annular recess 136 such that the ingested fluid flowing about pump 52 may be collected and exhausted through outlet 114.

The pump impeller 52 is split through the web connecting front and rear portions 126 and 128, and these portions are drilled, as at 66 and 68, such that a pin 70 may drivingly connect the respective portions. In additiou, the front portion 126 is provided with a bleed passage 72 to allow liquid pressure to communicate with space 74 between impellers 126 and 128. Furthermore,

' a plurality of springs 76 are interposed with portions 126 and 126 upon assembly to force the portions away from each other.

In this embodiment, the rear face of the housing cavity 124 is smoothly machined and the rear impeller is pro vided with bearing surfaces 73 to establish a reduced friction running contact maintained by spring and fluid pressure for reasons above mentioned.

I have no doubt that other forms of my invention can be designed than those I have disclosed above. Therefore, it is my intent that the true spirit of my invention is found in the appended claims.

I claim:

1. A centrifugal pump comprising:

a housing having an internal cavity fed by an axial inlet and a peripheral outlet;

a fluid collecting pocket in the inletladjacent the cavity;

a first pump impeller rotatably mounted in said housing cavity receiving fluid from said inlet and discharging same through said peripheral outlet;

a second pump impeller adapted to be driven concurrently with said first pump impeller and facing in an opposite direction to that of said first impeller in said cavity;

a resilient means interposed with said first and second impellers to project said second impeller outwardly of said first impeller whereupon running contact is maintained between said second impeller and a housing cavity wall; and

an internal passage connecting said fluid collecting pocket to an opening in the Wall in rubbing contact with said second impeller.

2. A centrifugal pump according to claim 1 wherein said first impeller contains a bleed passage communicating fluid pressure of said first impeller therebehind.

3. A centrifugal pump according to claim 1 and further comprising an outlet passage in said housing communicating an additional opening in the wall contact ing said second impeller to exhaust the fluid pumped thereby from said fluid collecting pocket.

4. A centrifugal pump comprising:

a liquid impeller;

a gas impeller;

a shaft for :rotatably driving said liquid impeller and said gas impeller, said liquid impeller and said gas impeller being mounted for concurrent rotation on said house on said shaft;

21 housing having an internal cavity in which said liquid impeller and said gas impeller are rotated, said housing being provided with an inlet passage leading to the cavity at one end thereof and with a plurality of outlet passages leading from the housing cavity, said housing also having an internal passage conmeeting a gas pocket chamber in the inlet passage adjacent the inlet connection to the cavity with the gas impeller; and

a force responsive means operatively connecting said gas impeller and said liquid impeller to urge said gas impeller outwardly from said liquid impeller to maintain running contact of said gas impeller and the housing structure around the cavity thereof adjacent opening-s into the cavity for said internal passage and one of said outlet passages.

References Cited by the Examiner UNITED STATES PATENTS 2,166,530 7/39 Morgan 103-113 2,358,744 9/44 Stepanoff 103-97 2,500,227 3/50 Adams 103-113 2,875,696 3/59 Zborowski 103-97 2,927,536 3/60 Rhoades 10397 3,045,602 6/62 Adams 103-113 KARL J. ALBRECHT, Primary Examiner. JOSEPH H. BRANSON, .TR., Examiner. 

1. A CENTRIFUGAL PUMP COMPRISING: A HOUSING HAVING AN INTERNAL CAVITY FED BY AN AXIAL INLET AND A PERIPHERAL OUTLET; A FLUID COLLECTING POCKET IN THE INLET ADJACENT THE CAVITY; A FIRST PUMP IMPELLER ROTATABLY MOUNTED IN SAID HOUSING CAVITY RECEIVING FLUID FROM SAID INLET AND DISCHARGING SAME THROUGH SAID PERIPHERAL OUTLET; A SECOND PUMP IMPELLER ADAPTED TO BE DRIVEN CONCURRENTLY WITH SAID FIRST PUMP IMPELLER AND FACING IN AN OPPOSITE DIRECTION TO THAT OF SAID FIRST IMPELLER IN SAID CAVITY; A RESILIENT MEANS INTERPOSED WITH SAID FIRST AND SECOND IMPELLERS TO PROJECT SAID SECOND IMPELLER OUTWARDLY OF SAID FIRST IMPELLER WHEREUPON RUNNING CONTACT IS MAINTAINED BETWEEN SAID SECOND IMPELLER AND A HOUSING CAVITY WALL; AND AN INTERNAL PASSAGE CONNECTING SAID FLUID COLLECTING POCKET TO AN OPENING IN THE WALL IN RUBBING CONTACT WITH SAID SECOND IMPELLER. 